Phase Diagram of the Sn–As–Ge System

Abstract

The paper presents the phase diagram of the Sn–As–Ge system. The diagram of polythermal Sn–GeAs section was constructed using the results of X-ray powder diffraction analysis and differential thermal analysis. We found that in a concentration interval with arsenic content of less than 50 mol%, four-phase peritectic equilibria  L + SnAs ↔ GeAs + Sn₄As₃ (834 К) and L + GeAs ↔ Ge + Sn₄As₃ (821 К) are present. When the temperature is close to the melting point of pure tin, non-variant equilibrium with tin, germanium, and Sn₄As₃ is implemented as well. The study of Sn_0.39As_0.61–Ge_0.28As_0.72, SnAs–Ge_0.4As_0.6 and SnAs–GeAs₂ sections and elaboration of the type of the SnAs–GeAs phase diagram demonstrated that polythermal sections SnAs–GeAs and SnAs–GeAs₂ can perform phase subsolidus demarcation of the phase diagram of the Sn–As–Ge system. There are also invariant peritectic equilibria L + GeAs₂ ↔ GeAs + SnAs (840 К) and L + As ↔ SnAs + GeAs₂ (843 К) in the system.